Since their introduction, sanitary napkins with adhesive attachment means, i.e., the so-called tabless sanitary napkins have proven to be a dominant force in the marketplace. Previous to the introduction of sanitary napkins having adhesive attachment means, napkins were constructed with long extensions at either ends called tabs. These tabs were attached to separate belts. The tabless sanitary napkins due to obvious advantages of convenience and comfort have almost universally supplanted these belted napkins.
While this shift in consumer preference has taken place in little more than a decade, there has been continuing effort directed towards developing a superior adhesive pattern which would provide secure attachment to undergarments and ease of release without either tearing the napkin or leaving substantial adhesive residue in the undergarment itself.
The most widely used and accepted pattern is that described in U.S. Pat. No. 3,672,371 issued to me, which provides for at least two centrally disposed narrow parallelly spaced lines of garment attachment adhesive. This pattern has been substantially, universally accepted and while the art is replete with attempts to design alternative configurations, the majority of the sanitary napkins currently sold in the United States utilize this configuration.
As discussed in my prior patent, a sanitary napkin during use is subjected to shear stress and other forces such as rotational torque applied to the napkin during movement by the wearer. It has been recognized, in fact, that the napkin will, during wear, actually become unattached and then reattach itself.
It has also been recognized that the napkin is subjected to side crushing forces which tend to permanently distort the napkin along each longitudinal edge. This crushing of the napkin can in some cases not only dislodge the napkin from its adhesive mooring, but can also distort the back surface of the napkin in such a manner as to provide for the contact of the centrally disposed adhesive lines with each other and therefor prevent the napkin from reattachment to the undergarment of the wearer.
While there are several different prior art configurations for adhesive pattern positioning, as for example disclosed in U.S. Pat. Nos. 3,575,175; 3,888,255; 3,897,783; and 3,973,567 or as set out in the prior art figures of U.S. Pat. No. 3,672,371 none of the prior art configurations provide the advantages of the pattern disclosed and claimed therein.